The present invention relates to a stator for use in a torque converter of an automatic transmission for automobiles and others.
Conventionally, a stator has been known, which has an annular stator body 1 having an inner annulus 2, a vane 3 and an outer annulus 4 concentrically integrally molded of a resin material such as a phenol resin, and in which a notch type one-way clutch 5 is provided on the inner peripheral side of the stator body 1, as shown in FIGS. 19 and 20.
In the conventional stator as described, the notch type one-way clutch 5 is constituted as follows:
That is, first, a pocket plate 6 made of metal in the form of annulus is secured by insert molding to the inner peripheral side of the stator body 1, and a notch plate 7 made of metal likewise in the form of annulus is combined with the pocket plate 6 relatively rotatably. As shown in section of FIG. 21, the fixed number of pocket portions 8 are equally arranged on an end portion 6a of the pocket plate 6, and struts 9 are supported by means of a spring 10 on the pocket portions 8 and encased therein for oscillation. The fixed number of engaging recesses 11 are equally arranged in an end portion 7a of the notch plate 7 opposite to the end portion 6a of the pocket plate 6, and one inner wall 11a in the peripheral direction of the engaging recess 11 is formed at a relatively acute rising angle so that the strut 9a comes in engagement (locking) with the inner wall 11a. On the other hand, the other inner wall 11b in the peripheral direction of the engaging recess 11 is formed at relatively gentle rising angle so that the strut 9 gets over (idle running) the inner wall 11b. Accordingly, by the provision of the engaging construction of the engaging recess 11 with the strut 9, when the notch plate 7 is intended to relatively rotate in the direction of A in the figure with respect to the pocket plate 6, the strut 9 comes in engagement with one inner wall 11a of the engaging recess 11 to prevent from relative rotation, allowing only the relative rotation in the opposite direction B.
In the stator provided with the one-way clutch 5 as described above, recently, there is a tendency that materials for components are changed from metal to resin from a viewpoint of lightening of parts and facilitation thereof, and as a part therefore, the stator having the pocket plate 6 formed of resin has been developed.
As shown in FIGS. 22 to 25, when the pocket plate 6 is formed of resin, the pocket plate 6 is also molded integral with the stator body 1 likewise made of resin, and the pocket portion 8 is also formed of resin. Accordingly, corner Rs 12a and 12b are provided on the pocket portion 8 in order to increase the strength of the pocket portion 8. The Rs 12a and 12b are formed in an inner corner portion of the pocket portion 8 with roundness of quarter circle or circular arc in section to disperse stress generated in the inner corner portion to thereby reinforce the inner corner portion, the roundness being formed in inner corner portions on both inner and outer sides (inside and outside) of a strut engaging surface 13 for supporting the strut 9 out of four inner corner portions of the pocket portion 8.
However, in the stator as shown in FIGS. 22 to 25, both the inner corner R 12a and the outer corner R 12b provided in the pocket portion 8 are formed to have the same size (radius dimension or radius of curvature), and the pocket portion 8 which opens substantially in the shape of rectangle with respect to the end portion 6a of the pocket plate 6 is formed with its longitudinal direction directed at a tangential direction of the stator body 1, thus sometimes posing an inconvenience as noted below.
That is, the stator in FIGS. 22 to 25 is fabricated, and the FEM analysis is made as follows: As a result of analysis, the outer corner R 12b is a stress concentrated portion, and stress generated in the outer corner R 12b is considerably larger than that generated in the inner corner R 12a. Accordingly, the strength of the outer corner R 12b is short, and the stator body 1 is possibly broken from the outer corner R 12b. 
It is an object of the present invention to provide a stator in which strength of an outer corner R provided in a pocket portion of a notch type resin-made stator is increased to thereby prevent the resin-made stator body from being broken from the outer corner R.
According to claim 1 of the present invention, there is provided a stator in which a pocket portion encasing a strut of a notch type one-way clutch is provided in a stator body made of resin, and corner Rs are provided on both inner and outer sides of a strut engaging surface in said pocket portion, the outer corner R being formed to be larger than the inner corner R.
According to claim 2 of the present invention, there is provided a stator in which a pocket portion encasing a strut of a notch type one-way clutch is provided in a stator body made of resin, and corner Rs are provided on both inner and outer sides of a strut engaging surface in said pocket portion, said pocket portion being formed to be inclined at a fixed angle in a tangential direction so that stress generated in the inner corner R is equal to or substantially equal to that generated in the outer corner R.
Further, according to claim 3 of the present invention, there is provided a stator in which a pocket portion encasing a strut of a notch type one-way clutch is provided in a stator body made of resin, and corner Rs are provided on both inner and outer sides of a strut engaging surface in said pocket portion, said strut engaging surface being arranged on a plane including a center axis of said stator body.
Furthermore, according to claim 4 of the present invention, there is provided the stator of claim 3, wherein width of the strut engaging surface is formed to be larger than that of other parts of the pocket portion, and corner Rs are provided in both inner and outer sides of said wide strut engaging surface.
In the corner Rs provided in the pocket portion of the notch type resin-made stator, when the outer corner R is formed to be larger than the inner corner R, stress generated in the outer corner R is widely diffused to thereby enable increasing strength of the outer corner R.
Further, when the pocket portion is inclined at a fixed angle in a tangential direction so that stress generated in the inner corner R is equal to that generated in the outer corner R, stresses generated in the inner corner R and the outer corner R are properly balanced so that the stress generated in the outer corner R is small to thereby enable increasing strength of the outer corner R.
Further, when the strut engaging surface is arranged on the plane including the center axis of the stator body, the stress generated in the inner corner R is likewise equal to or substantially equal to that generated in the outer corner R. Accordingly, stresses generated in the inner corner R and the outer corner R are properly balanced so that the stress generated in the outer corner R is small to thereby enable increasing strength of the outer corner R.
Further, when width of the strut engaging surface is formed to be larger than that of other parts of the pocket portion, and corner Rs are provided in both inner and outer sides of said wide strut engaging surface, the respective corner Rs are enlarged. Accordingly, stress generated in the outer corner R is widely diffused.
The present invention takes effects as follows:
According to the stator of claim 1, in the corner Rs provided in the pocket portion of the notch type resin-made stator, the outer corner R is formed to be larger than the inner corner R. Therefore, stress is widely diffused in the outer corner R to thereby enable increasing strength of the outer corner R. Accordingly, strength of the outer corner R is increased to enable preventing the outer corner R from occurrence of inconveniences such as cracks and to prevent the resin-made stator body from being broken from the outer corner R.
According to the stator of claim 2, the pocket portion is inclined at a fixed angle in a tangential direction so that stress generated in the inner corner R is equal to or substantially equal to that generated in the outer corner R. Therefore, stresses generated in the inner corner R and the outer corner R are properly balanced, and stress generated in the outer corner R is small, to thereby enable increasing strength of the outer corner R. Accordingly, strength of the outer corner R is increased to enable preventing the outer corner R from occurrence of inconveniences such as cracks and to prevent the resin-made stator body from being broken from the outer corner R.
According to the stator of claim 3, since the strut engaging surface is arranged on the plane including the center axis of the stator body, stress generated in the inner corner R is equal to or substantially equal to that generated in the outer corner R. Therefore, stresses generated in the inner corner R and the outer corner R are properly balanced, and stress generated in the outer corner R is small, to thereby enable increasing strength of the outer corner R. Accordingly, strength of the outer corner R is increased to enable preventing the outer corner R from occurrence of inconveniences such as cracks and to prevent the resin-made stator body from being broken from the outer corner R.
In addition, according to the stator of claim 4, width of the strut engaging surface is formed to be larger than that of other parts of the pocket portion, and corner Rs are provided in both inner and outer sides of said wide strut engaging surface. Therefore, the corner Rs are enlarged, and stress is widely diffused also in the outer corner R. Accordingly, strength of the outer corner R is increased to enable preventing the outer corner R from occurrence of inconveniences such as cracks and to prevent the resin-made stator body from being broken from the outer corner R.